In a disc brake, the brake caliper is generally arranged straddling the outer peripheral margin of a brake disc, adapted to rotate about a rotation axis defining an axial direction (X-X). In a disc brake, a radial direction (R-R), arranged substantially orthogonal to said axial direction (X-X), and a tangential or circumferential direction (C-C), orthogonal to both said axial direction (X-X) and said radial direction (R-R), are further defined.
The brake calipers are constrained to a supporting structure which remains stationary with respect to the vehicle, such as, for example, a spindle of a vehicle suspension or a vehicle wheel hub. The brake caliper usually comprises a caliper body comprising two elongated portions arranged so as to face opposite braking surfaces of a brake disc and at least one bridge, which connects said two elongated portions to each other.
In a typical arrangement of a disc brake on a vehicle, a braking surface of the brake disc faces the vehicle defining the vehicle-side disc brake and the opposite braking surface of the brake disc faces the vehicle wheel defining the wheel-side of the disc brake. So, when the brake caliper is mounted on a brake disc, a first elongated portion of the caliper body is on vehicle-side and a second elongated portion of the caliper body is on wheel-side. Brake pads are provided arranged between each elongated portion of the caliper body and the facing braking surfaces of the brake disc. At least one of the elongated portions of the caliper body has cylinders adapted to accommodate hydraulic pistons capable of exerting a thrust action on the Brake pads, abutting them against the braking surfaces of the disc to apply the braking action on the vehicle.
This braking action on the vehicle applies a considerable friction adapted to create the desired braking torque on the vehicle itself, the braking torque in all cases contextually transforming the motion energy of the vehicle into heat, which is accumulated in the disc and in the pads. The heat from the braking surfaces extends into the entire body of the brake disc, radiating and consequently heating and sometimes overheating, the caliper body which is arranged straddling it, sometimes deteriorating the properties, e.g. the mechanical properties, of the material of which the brake caliper is made.
Indeed, the need to limit the unsprung vehicle weights to the maximum leads to making caliper bodies of strong materials which are as light as possible. For example, the caliper bodies are made of aluminum or aluminum alloys which have particular mechanical strength and a sufficiently low weight, the strength being equal. Brake calipers having caliper bodies made either entirely or partially of composite material, which may be even more sensitive to heat stress than aluminum, have recently been suggested.
The need to protect the caliper body, in particular in its zone bridge-arranged straddling the disc and in its portions facing the brake disc, is thus strongly felt.
Document JP2015110985 shows a heat shield element of a radial portion of a floating body of a brake caliper. This known solution is suitable for small floating calipers having a limited circumferential extension which does not expose the elongated elements on vehicle-side, and even less so those on wheel-side, to directly face the overheated surfaces of the brake disc.
The need is thus strongly felt to provide a heat protection for the caliper body, where the latter has a circumferential extension which exposes the connection points of the elongated elements to directly face the overheated brake disc, together with the parts of the elongated portions which directly face the braking surfaces by extending circumferentially by the side of the brake pads, which constitute a heat barrier in themselves.
Such a need is particularly felt in the brake calipers used for high-performance vehicles, which for structural purposes, have considerable circumferential extensions adapted to stiffen the elongated portions on vehicle-side and on wheel-side with the end bridges. Such circumferentially extended bridges stiffen the behavior of the brake caliper which is suitable for strong stresses, such as those applied during the hard braking required for quick vehicle decelerations. Furthermore, these rapid decelerations determine greater concerned energies, and thus greater heating of the brake disc and thus greater mechanical stresses for the caliper body.
Therefore, the need is strongly felt to protect the bridge zone of the caliper body as well as the adjacent elongated portions.
The need is also felt to manufacture these heat protections in a simple and quick manner in terms of construction and assembly, without losing their efficacy in all cases.